But, how safe is it? On transgenics, cisgenics, and mutants.

Good news from Africa – “Scientists and crop researchers at Kenya´s Agricultural Research Institute (KARI) developed the new wheat seeds over the past decade. Through a process called ‘mutation plant breeding’, they applied radiation-based techniques to modify crop characteristics and traits.” In 2001, KARI plant breeders released Njoro-BW1, their first mutant wheat variety. It is drought tolerant, moderately resistant to rust (a fungus), has good yield, and good flour quality. “Kenya´s plant breeders soon will release a second mutant wheat variety, code-named DH4, which shares most of the same good qualities of Njoro-BW1.” [Golden Wheat “Greens” Kenya´s Drylands]Traditional breeding encompasses all plant breeding methods that do not fall under current GMO regulations.As the European legal framework defines GMOs and specifies various breeding techniques that are excluded from the GMO regulations,we use this framework as a starting point, particularly the European Directive 2001/18/EC on the deliberate release of GMOs into the environment (European Parliament, 2001). Excluded from this GMO Directive are longstanding cross breeding, in vitro fertilization, polyploidy induction, mutagenesis and fusion of protoplasts from sexually compatible plants (European Parliament, 2001).It is indeed good news that Kenyan farmers have these lines of wheat with such improvements over unimproved varieties. However, radiation based so-called mutation plant breeding could have unintended changes in the genome. This technique, widely used in both organic and conventional crops, literally bombards the seeds with radiation. The seeds are allowed to germinate, and interesting mutants are used to create new lines. The problem is that multiple mutations can occur in the same seed, and some of those mutations may go undetected.
A February report entitled “Microarray analyses reveal that plant mutagenesis may induce more transcriptomic changes than transgene insertion” from the National Institute of Health in Portugal indicates that this plant breeding tool may not be the best idea. The last few sentences of their abstract sums it up:

Wefound that the improvement of a plant variety through the acquisitionof a new desired trait, using either mutagenesis or transgenesis,may cause stress and thus lead to an altered expression of untargetedgenes. In all of the cases studied, the observed alterationwas more extensive in mutagenized than in transgenic plants.We propose that the safety assessment of improved plant varietiesshould be carried out on a case-by-case basis and not simplyrestricted to foods obtained through genetic engineering.

Transgenesis is the genetic modification of a recipient plant with one or more genes from any non-plant organism, or from a donor plant that is sexually incompatible with the recipient plant. This includes gene sequences of any origin in the anti-sense orientation, any artificial combination of a coding sequence and a regulatory sequence, such as a promoter from another gene, or a synthetic gene.Trying to regulate GM or non-GM as broad categories are impossible, because each resulting plant variety is going to have its own “quirks”. If DH4 and Njoro-BW1 have been extensively tested for unwanted alteration in gene expression and subsequently released for general use, then they are reasonably safe (remember, nothing is definitive in science). Similarly, if transgenic plants such as Sub1A-1 rice have been tested and released, then they too can be used without worry.
However, if plant varieties mutated with radiation are not adequately tested before release, then we might all have something to worry about.To my knowledge, only Canada requires testing of these crops. We can’t even assume that traditional breeding by cross pollination is 100% safe because of natural mutation and new combinations of genes and alleles. Tomatoes, potatoes, and celery all naturally produce some nasty toxins. We’ve mostly bred them out, but there have been cases where the toxins appeared at higher levels through traditional breeding. These plants have much higher probability of danger for consumers than transgenic plants, but don’t have to be tested at all under current regulations in the US or EU.Intragenic or cisgenic plants are our best opportunity for safe enhancement of food crops (cis- means same). This is a form of genetic engineering that uses the plant’s own genome as a source for new traits instead of other non-related organisms (has also been called GM-lite). To learn more about the idea, please see www.cisgenesis.com.Cisgenesis is the genetic modification of a recipient plant with a natural gene from a crossable—sexually compatible—plant. Such a gene includes its introns and is flanked by its native promoter and terminator in the normalsense orientation.Cisgenic plants can harbour one or more cisgenes, but they do not contain any transgenes.Some people, including myself, beleive that cisgenic crops should be regulated differently from transgenic crops that express proteins that don’t normally occur in that species. The applications of cisgenics are more limited than transgenics, but still there is a lot to be done. A great example of cisgenics is gene silencing, which can be used to inactivate unwanted genes, such as those that cause toxins. Examples that are currently being researched are less carcinogenic tobacco and rice that can more easily form hybrids. All of the benefits in KARI’s mutated wheat could have been accomplished with cisgenics.
JR Simplot is a company that is particularly interested in cisgenics, and has produced a lot of literature that essentially says that Monsanto’s way of creating new plant lines is not the right way. I think there’s room for both, but agree that cisgenics are inherently safer. I especially like the idea that cross pollination between cisgenic plants and wild varieties won’t be a problem, since these things could have all happened naturally anyway. The idea of cisgenics has been around for quite a few years now, but scientists need to talk with the public about it, so the public can talk to their government representatives, so the representatives can go about getting the regulations changed.
Images from “Cisgenic plants are similar to traditionally bred plants: International regulations for genetically modified organisms should be altered to exempt cisgenesis”.

Anastasia Bodnar serves as the Policy Director of Biology Fortified, Inc. She is a science communicator and multidisciplinary risk analyst with a career in federal service. She has a PhD in plant genetics and sustainable agriculture from Iowa State University.

Post navigation

5 comments

Hmm, I didn’t know there was a different term for plants transformed with their own genes. But yeah, when you tweak a gene or two already in the plant, whether by RNAi or knockouts, or by changing a promoter or otherwise altering regulation, the risks are far lower than wide crosses, transgenics, or mutagenesis.